Connecting the start-up relay of the refrigerator: instructions with photos and diagrams

The start-up protection relay is a small but critical element of the refrigerator, which is responsible for starting the compressor and protecting it from overloads. If your refrigerator stops turning on, makes a loud noise, or turns off a few seconds after starting, the problem may lie in this particular unit. Replacing or connecting a new relay is a task that you can handle yourself, without resorting to the services of a specialist. However, it is important to act carefully here: incorrect connection will not only not solve the problem, but can also damage the compressor or electronics of the refrigerator.

In this article we will figure out how to correctly connect the start-up relay to refrigerators of different brands (Atlant, Indesit, Stinol, LG, Samsung and others), what tools are needed, how to read connection diagrams and what mistakes beginners most often make. You will also learn how to check the functionality of the relay before installation and what to do if, after connecting, the refrigerator still does not work. For clarity, we will provide photographs of real relays, connection diagrams and a compatibility table with popular compressor models.

Before starting work, make sure that the problem is in the relay. Typical signs of its malfunction: the compressor does not start (no characteristic hum), the refrigerator turns on and turns off immediately, the relay clicks, but the motor does not starts. If the compressor hums but does not freeze, the reason may be a freon leak or a clogged capillary tube - this will require specialist diagnostics.

1. Design and principle of operation of a start-up protection relay

A start-up protection relay (sometimes called start relay or compressor relay) performs two key functions: compressor start at the moment of switching on and protection from overheating or overload current Modern refrigerators use two types of relays:

• 🔧 Electromechanical (induction) - the most common, consist of a coil, core and contacts. The operating principle is based on electromagnetic induction.
• 📱 Electronic (posistor) - use semiconductor elements (posistors) that change resistance depending on temperature. More often found in refrigerators Samsung, LG and Liebert.

How does it work? When the refrigerator is turned on, voltage is applied to the relay winding, which closes the contacts of the compressor starting winding. After the rotor accelerates, the starting winding is turned off, and the working winding continues to function. If the current exceeds the permissible value (for example, due to a jammed compressor), the relay opens the circuit, preventing overheating.

It is important to understand that the relay is selected for a specific compressor by several parameters: type refrigerant (R134a, R600a), compressor power (usually indicated on its body) and operation current. For example, for compressors Danfoss series NL or SL relays are suitable DANFOSS 103N0010, and for Embraco EG — Embraco ER35.

How to distinguish a starting relay from a thermostat?

The starting relay is attached directly to the compressor and has 2-4 pins for connecting wires. The thermostat (thermostat) is usually located inside the refrigerator compartment and connected to the light bulb.

2. Tools and materials for connection

To replace or connect a start-up relay, you do not need complex equipment. Here is a minimum set of tools:

• ⚡ Phillips and flathead screwdriver — for dismantling the compressor cover and mounting the relay.
• 🔌 Multimeter —for checking the circuit and resistance of the compressor windings.
• 📏 Pliers or wire cutters — for crimping terminals (if the wires do not have connectors).
• 🔍 Flashlight —lighting the compressor compartment (usually it is located at the bottom of the refrigerator).
• 📝 Marker or stickers — for marking wires when disconnected.

Also prepare: new relay (must correspond to the compressor model), insulating tape or heat-shrink tube to isolate connections, and terminals or connectorsif the old ones are damaged. If you are not sure about the relay model, take a photo of the old one and show it to the seller at the spare parts store - he will help you choose an analogue.

Safety warning: before starting work be sure to disconnect the refrigerator from the mains and discharge the compressor capacitorby shortening its leads with a screwdriver with an insulated handle. The capacitor can store a charge of up to 300 V, which is dangerous to life!

3. Relay connection diagrams for different compressors

The connection diagram depends on the type of compressor and the number of pins on the relay. Below are the three most common schemes:

To determine which output is responsible for what, look at the compressor housing: usually there is marking there: C (Common - common), S (Start - starting winding), R or M (Run/Main - working winding). If there is no marking, use a multimeter:

1. Set the resistance measurement mode (Ω).
2. Measure the resistance between all pairs of terminals. The largest value (for example, 20–40 Ohms) is C + S, the average (10–20 Ohms) is C + R, and the smallest (2–5 Ohms) is S + R.

Attention! ⚠️ If there are four terminals on the compressor, the fourth usually goes to thermal protection or temperature sensor. Do not connect it to the relay - this may damage the electronic control unit.

4. Step-by-step instructions for connecting a relay

Now let's move on to practice. Follow these instructions to connect the relay correctly:

1. Step 1. Removing the old relay

   Unplug the refrigerator. Remove the compressor protective cover (usually it is secured with 2-4 screws). Carefully disconnect the wires from the relay, first photographing or sketching their location. If the wires are connected through terminals, loosen them with a screwdriver; if soldering, use a soldering iron.

2. Step 2. Checking the compressor

   Before installing a new relay, make sure that the compressor is working. Measure the winding resistance with a multimeter (see section 3). If the resistance between any terminals approaches zero or infinity, the compressor is faulty and requires replacement.

3. Step 3. Installing a new relay

   Attach the new relay to the compressor in the same position as the old one (usually it is secured with a latch or screw). Connect the wires according to the diagram:

   • 🔌 Phase wire (usually brown or black) - to the terminal C (common).
   • 🔄 Wire from the working windings (blue or red) - to the terminal M/R.
   • ⚡ Wire from the starting winding (yellow or white) - to the output S.

Step 4. Checking the connection

Make sure that all connections are securely fastened and the exposed parts of the wires are insulated. Plug in the refrigerator. If the relay clicks, but the compressor does not start, check:

• The correct connection of the wires (possibly mixed up S and M).
• The voltage in the socket (should be 220-240 V).
• Integrity of the starting capacitor (if it is in the circuit).

If after connecting the compressor starts, but the refrigerator does not freeze, the problem may be freon leak or thermostat malfunctionIn this case, diagnostics using a pressure gauge will be required.

5. Connection features for different brands of refrigerators

Although the principle of operation of the relay is the same, there are nuances in refrigerators of different brands. Let's consider them in more detail:

Atlant And Minsk

Most models (Atlant XM-4021, Minsk 126) use compressors Danfoss or Secop The relay is attached directly to the compressor housing and has a plastic casing. Please note: in some older models the relay is combined with thermostat - its replacement requires soldering.

Indesit i Stinol

Compressors are often found here Embraco (series EG, NE). The relay can be either mechanical (Embraco ER35) or electronic (Sensodrive). refrigerators Indesit with a system No Frost the relay is sometimes integrated into the control board - its replacement requires complete disassembly of the electronic unit.

Samsung i LG

Modern models (Samsung RB-30 J3200, LG GA-B409) are equipped with inverter compressors and electronic relays. It is important here:

• 🔌 Use only original spare parts (for example, Samsung DA97-02493A).
• 📱 Connect the relay strictly according to the diagram from the service manual (it may differ from the standard one).
• ⚠️ Do not touch the control board without an antistatic wrist strap.

Attention! ⚠️ In refrigerators with electronic control (for example, Liebert or Beko) replacing the relay may require resetting errors through the service menu. Without this, the refrigerator will not start. to reset, you need to press a combination of buttons on the panel (check the instructions for the model).

6. Typical mistakes and how to avoid them

Even experienced professionals sometimes make mistakes when connecting a relay. Here are the most common ones and ways to prevent them:

• 🔌 Wrong connection of the wires — the starting and working windings are mixed up. Solution: always mark the wires before disconnecting and check the diagram.
• 🔧 Bad contact —oxidized or weakly clamped terminals. Solution: clean the wires and terminals with sandpaper, crimp with pliers.
• ⚡ Ignoring the compressor test - connecting the relay to a faulty compressor. Solution: always check the resistance of the windings with a multimeter.
• 📉 Mismatch between the relay and the compressor —for example, a 5 A relay is installed on a compressor with a current of 8 A. Solution: check the technical specifications (the operating current is indicated on the relay body).
• 🔥 Lack of insulation —bare wires can cause a short circuit. Solution: use heat-shrinkable tubing or electrical tape.

Another common problem is the relay clicks, but the compressor does not. startsThe reasons may be the following:

• Faulty starting capacitor (if it is in the circuit).
• The compressor rotor is jammed (checked manually: when the power is off, the rotor should rotate freely).
• The mains voltage is too low (less than 190 V).

What to do if the relay gets hot?

If the relay gets hot during operation, this may be normal (especially for induction models), but if it is too hot to touch, check:

- Correspondence between relay and compressor current.

- Quality of contacts (poor contact leads to heating).

- Presence of a short circuit in the compressor windings.

7. Checking operation after connection

After installing the relay, you need to make sure that the refrigerator is working correctly. Follow this algorithm:

1. Plug in the refrigerator and listen:
   • 🔊 Click. relay - it’s normal, it closes the contacts.
   • 🔄 Compressor hum — means that it has started.
   • ❌ Silence or repeated clicks —a problem with the connection or the compressor.

Check temperature:

• After 1-2 hours of operation, touch the condenser (the grill at the back of the refrigerator). It should be warm, but not hot.
• The temperature in the refrigerator compartment should begin to drop (check with a thermometer).
• Current control:

  If there are current clamps, measure the current consumption. It should correspond to the compressor's nameplate values (for example, for Danfoss NL50 this is ~0.8–1.2 A in operating mode). If the current is higher, the compressor is overloaded.

If the refrigerator starts, but turns off after a few minutes, there are two possibilities. reasons: relay protection is triggered (check the current and resistance of the windings) or thermostat is faulty (it can open the circuit ahead of time).

8. When is it better to contact a specialist?

Although connecting a relay is a task that is feasible for most users, in some cases it is better to call a specialist:

• 🔧 If compressor does not start even after replacing the relay - there may be a problem in the windings or electronics.
• ⚡ If the refrigerator with electronic control (display, touch buttons) and after replacing the relay an error is displayed.
• 🧊 If required soldering wires (for example, in old models ZIL or Turk).
• 🔥 If you feel burning smell or see traces of melting on the wires, this is a sign of a short circuit.
• 📉 If the refrigerator works, but does not freeze —possibly a freon leak or a clogged capillary tube.

The cost of replacing the relay in a service center is usually 1500–3000 rubles (including diagnostics. If you are not confident in your abilities, it is better to pay for repairs than to risk an expensive one). compressor.

Attention! ⚠️ In refrigerators with inverter compressors (Samsung Digital Inverter, LG Linear Compressor), replacing the relay requires special equipment to configure the control board. Incorrect connection can damage the entire unit.

FAQ: Frequently asked questions about connecting a start-up relay

Is it possible to connect a relay from one refrigerator to another?

Theoretically, it is possible, but only if:

• 🔧 The compressors are identical in model and power.
• 📏 The relay operation current corresponds to the compressor current.
• ⚡ The relay type is the same (electromechanical or electronic).

For example, a relay from Atlant XM-4021 suitable for Minsk 15Mif they have the same compressors Danfoss NL35. But it is better to use the original relay or an analogue recommended by the manufacturer.

Why does the new relay click, but the compressor does not start?

Reasons several:

1. The starting and operating winding wires are mixed up.
2. The starting capacitor is faulty (if it is in the circuit).
3. The compressor rotor is jammed (checked manually: when the power is turned off, the rotor should rotate freely).
4. The voltage in the network is too low (less than 190 V).

Check all options in order.

How to check a relay with a multimeter?

To check an electromechanical relay:

1. Install a multimeter to resistance measurement mode (Ω).
2. Connect the probes to the C i Sterminals. In the normal state, the resistance should be infinite (open).
3. Apply a voltage of 220 V to the relay coil (terminals C and M). If the relay is working properly, the contacts will close, and the resistance between C and S becomes 0 Ohm.

For an electronic relay, checking is more difficult - you need an oscilloscope or a test in the working circuit.

What will happen, if you connect the relay incorrectly?

The consequences depend on the type of error:

• 🔌 The windings are mixed up —the compressor will not start, but the relay will click.
• ⚡ Short circuit —the fuse will burn out or the board will be damaged controls.
• 🔥 Current mismatch —the relay will overheat and quickly fail.

In the best case, the refrigerator simply will not turn on, in the worst case, the compressor will burn out.

Where to buy a start-up protection relay for a refrigerator?

The relay can be purchased:

• 🏬 In spare parts stores for household appliances (for example, 220 Volt, M-Video).
• 🌍 In markets like Avito or Yula (but the risk of running into a fake).
• 📦 In online stores (AliExpress, Wildberries) - but you will have to wait longer for delivery.

The average price of a relay is from 500 to 2000 rubles, depending on the model Always take a receipt and check the relay before. installation.